Grain door



Jan. 25, 1955 E, STACK 2,700,192a

GRAIN DOOR Filed Jan. 8, 1952 United States -Patent 'O GRAIN Doo'RQ f v Emmet G. Stack, Portland, Oreg. Application January 8, 1952, Serial No. 265,481 z claims. (ci. zei-30)' My invention relates to improvements in grain doors used in loading grain in box cars. A

Some of the objectives of this invention are: an easier installation of the grain door; an easier release of the grain; an easier removal of the door; and a minimizing of the damage common to the installation and removal of grain doors.

Another objective is to provide a grain door whichA offers less incentive to theft.

A further and very important objective is to provide a grain door which may be constructed of plywood.

A number of features set forth in the co-pending application of Horner S. Sackett and Emmet G. Stack, Ser. No. 237,376, are applicable to the grain door described herein.

rIwo types of grain doors are in common use today, namely, the lumber door which comprises two courses of 2%2 lumber of approximately 1000# stress material cleated and nailed together, and a paper door enclosing steel wires.

The lumber door is becoming costly and hard to get. The paper door is cheap but it is only a one-trip door. However, its cheapness is offset by damage claims which have reached proportions that are of great concern to the railroads.

Now that waterproof plywood is coming down to a price which brings it Within shooting distance of the lumber door a way to use it cheaply is being sought.

In our co-pending application we pointed out that W unsanded r plywood equals the lumber door, previously mentioned, in strength. The feature of the above mentioned plywood door is that the several sections which go to make up the door may be varied in thickness in keeping with the lateral pressure of the grain thereagainst, which pressure varies from top to bottom, thus each door section from the bottom to the top may be made from a thinner and less costly plywood sheet.

The construction of the grain door to be described herein is such `that the minimum thickness of commercial plywood may be used for the bottom door section hence the same thickness of plywood may be used for all door sections. However, it is to be seen that the plywood sheets for each door section may be varied in thickness, or, the thickness of the spacers between the covers may be increased in depth.

Fig. 1 of the drawings accompanying the application is an elevation showing how the door sections are stacked in use; Fig. 2 is a diagrammatic section thru a box car showing the relatiion of the lateral pressure caused by grain against the door; Fig. 3 is a plan view of a door section having a double spacer; Fig. 4 is a plan View of a door section having a single spacer; Fig. 5 is a vertical section on the line S-S of Fig. 3; Fig. 6 is a vertical section on the line 6 6 of Fig. 4; Fig. 7 is an isometric elevation of the door section shown in Fig. 4, arranged to show the method of applying the glue or adhesive to hold the plywood covers together; Fig. 8 shows the lifting jack dado; Fig. 9 shows a steel clip used to hold the door sections against the box car side.

Thruout the drawings and the specification similar numerals refer to similar parts.

In what I believe to be the present preferred form of the door D, to be described, comprises two spaced apart spacer strips 1 over which are sprung two plywood covers 2 and 3 having greater length than width which have their ends or shorter sides 4 and 5 glued together for a short distance. The spacer strips 1 are ice cut-in between a sill 6 and la header 7. The covers 2 and 3 are glued to the spacers, sill, and header. When?` two spacers 1 are used they are positioned on the thirdl points or lf of the door section length and when only one spacer is used, as in Fig. 4, it is positioned on the centerline or y; of said door section. f

In the manufacture of this plywood door, time and` heat play a very important role in the matter of costs.l To keep the c ost do-wn so that the plywood door may.' compete with the built-up lumber door is a problem.

Fig. 7 shows how this problem may be met and con-. struction expedited.

Case'in glue is spread over an area 8 on each endv of a.`cover as 2. Over similar areas 9 of cover 3 is, spread a hardener as Laucks Speedbond. Surround-i ing areas 8 and 9 as 10 is spread the phenolic or watel'-,` proof adhesive used. When thus prepared the cover ends 4 and 5 are engaged by suitable clamping means, none being shown. When the hardener is brought into contact with the casein glue the latter gels and within a matter of minutes the door section may be removed from the clamping means and put in storage where the phenolic adhesives 9, which surround the casein glue 8 and prevent moisture from reaching it, may set with time and/or heat.

Tests have shown that /s sanded commercial plywood make a door section stronger than the built-up lumber door mentioned when glued to 1%" square spacers, sill, and header. A 4" wide glue area appears to be adequate for the cover ends.

The railroads suler considerable loss thru the theft of the built-up lumber doors for they may be easily taken apart without wrecking them. Their shape, as is, precludes the use of the plywood door for many purposes.

The grain door is preferably made up of three 2 sections S set up in stacked relation as shown in Fig. l, to form a six foot barrier across the box car door opening O. They may be held in this relation by various means some of which are shown and described in our co-pending application. One of these means is illustrated herein. It consists of a short piece of spring steel about 21/2" long, 1%" wide, and of .028 stock. One end is provided with nail holes for the reception of the shingle nails 12 by which the clip 11 is secured to the door jamb or car lining 13. The other end may be shaped to form a shoulder 11A to better position the clip 11 when it is being installed. Two of these clips 11 are used on each end of each door section S. Invariably the car loaders will drive anywhere from two to fivev 20d spikes thru the lumber door into the car door jamb or lining 13.

When a car is to be unloaded it is placed over a pit and a hydraulic jack with a special foot is driven under the bottom door section and all the door sections forced up until the grain may flow out from under the bottom section. The spikes are sheared oi or pulled out of the door sections or the car jamb or lining 13, thus damaging both the door sections and the car jamb or lining or both. No nails need be driven into the door sections described in the co-pending application or in this one. The use of the clip 11 or any of the means described permit the door sections to be readily moved upwardly.

In order to prevent damage thru the use of the jack a dado 14 is provided in the bottom door section for the insertion of the jack foot. Since thinner plywood may be used with the door section described herein a sill 6 and a header 7 is provided between which the spacers 1 are cut. The sill provides more area for the jack to engage and prevents the crushing of the covers 2 and 3. When the door section is built with a single spacer 1 the dado 14 may be positioned directly under said spacer 1. The sill 6 and header 7 might be eliminated if it were desirable to sacrifice some of the door section life.

It will be noted that there is a void 15 between the covers in either of the door sections shown and described into which the clips 11 and the nails-12 may be inserted for shipment. It is also quite evident that this space 15 may be filled with grain which naturally provides support between the covers 2 and '3 during 'the shipment of grain.

It is 'to be understood that while I have specically mentioned the use of plywood other sheet material having adequate strength in compression and tension may be used. It may also be remarked that 1% unsanded r plywood having an 'ample lsection modulus may 'be used in lieu "of the sanded commercial 1%" thickness.

What is 'new inthe art follows:

1. A grain door 'section' including vtwo cover sheets of greater length than width having the end portions o'f ltheir adjacent narrow ends glued to each other "to leave Yaiiat bearing surface on both :sides-of :both ends of the door 'section and a 'rectangular framework 4having parallel faces to which the cover 1sheets are se cured lpositioned between the cover 'sheets to spread them apart between their glued together ends 4said framework occupying and en'ccnnp'assing; an area approximating the middle third 'area of the cover sheets whosefend portions converge from rsaid middle `area toward their glued together Yends.

2. A grain door section including two cover 'sheets of greater length than width having the end portions of their adjacent narrow ends glued to each other to leave a flat bearing surface on both sides of both ends of the door section and a rectangular framework having parallel faces to which the cover sheets are secured positioned between the cover sheets to spread them apart between their glued together ends said framework being positioned to form the cover sheets with a parallel middle portion and a tapered port-ion on each end thereof which extends between said middle portion and the respective glued `together ends of said cover sheets.

References Cited in the file of this patent UNITED :STATES PATENTS 2,311,170 Hain Feb. 16, 1943 2,479,819 Ragon Aug. 23, 1949 FOREIGN `PATElslTS 590,396 Great Britain July 16. 1947 

